ARP 4005 VCA Sub-Modules

The 4005-1P, 2N and 3P were encapsulated differential input variable gain sub-modules (A.K.A. VCA).

 

4005-1P

Parts Placement and SCHEMATIC - (click on image to download full-sized version)

PCB - actual size
Used for all 3

PARTS LIST

Transistors
TZ-81 *Q3
TZ-581 **Q4, Q5
TZ-81Q1, Q2 (matched pair)

 

4005-2N

Parts Placement and SCHEMATIC - (click on image to download full-sized version)

PCB - actual size
Used for all 3

PARTS LIST

Tempco Resistors1/4 watt, 3%, +3500ppm
100 OhmR1
Transistors
TZ-81 *Q3
TZ-581 **Q4, Q5
TZ-81Q1, Q2 (matched pair)

 

4005-3P

Parts Placement and SCHEMATIC - (click on image to download full-sized version)

PCB - actual size
Used for all 3

* - TZ-81 alternate part was the 2N5249, also defunct. 2N3904 would be a modern equivalent.

** - TZ-581 alternate part was the 2N5367, also defunct. 2N3906 would be a modern equivalent.

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